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Internal
ORA000001 CDMA Basic Communication Flow
(NSS)
ISSUE 1.0
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Upon completion this course, you will be able to:
Understand the basic flows of CDMA.
Understand the meaning of important
parameters.
Improve the problem analysis and fault locating
capabilities according to the flows.
Memorize the abbreviation of signaling
messages..
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References
CSOFTX3000 Technical Manual-
Service Procedures
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Chapter 1 Brief Introduction of CDMA FlowsChapter 1 Brief Introduction of CDMA Flows
Chapter 2 Procedures for Mobility ManagementChapter 2 Procedures for Mobility Management
Chapter 3 Procedures for Security Management Chapter 3 Procedures for Security Management
Chapter 4 Procedures for Basic Call Service and Chapter 4 Procedures for Basic Call Service and
Short Message ServiceShort Message Service
Chapter 5 Procedures for Intelligent Network SerChapter 5 Procedures for Intelligent Network Ser
vicesvices
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Brief introduction of CDMA flows
Basic CDMA flows
Registration flows
Authentication flows
Calling flows
Handoff flows
Supplementary service flows
Short message flows
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Brief introduction of CDMA flows
The flows that the main services may involved in are as follows:
Mobile phone power on/off: location updating flows and authentication flows
Mobile phone calling: calling flows and authentication flows (IN flows)
Migration in the conversation: handoff flows and authentication flows
Short message: short message flows and authentication flows
Supplementary service: supplementary service flows and authentication
flows
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Chapter 1 Brief Introduction of CDMA FlowsChapter 1 Brief Introduction of CDMA Flows
Chapter 2 Procedures for Mobility ManagementChapter 2 Procedures for Mobility Management
Chapter 3 Procedures for Security Management Chapter 3 Procedures for Security Management
Chapter 4 Procedures for Basic Call Service and Chapter 4 Procedures for Basic Call Service and
Short Message ServiceShort Message Service
Chapter 5 Procedures for Intelligent Network SerChapter 5 Procedures for Intelligent Network Ser
vicesvices
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Overview of Mobility Management
The network supports and manages mobility of a MS to:
Determine the current location of the MS.
Optimize the connection between the MS and network.
Roaming means that a MS changes the connection to a cell
and to the network. According to different statuses of a MS,
mobility management falls into location management and
handoff management.
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Location Management
It is necessary to confirm the current location of an idle MS. Location management helps the MS to be connected to the calling party promptly and helps the network keep tracing and store the current location information of a MS. Location management guarantees the consistency of the location information stored in the HLR, MSC/VLR, and MS.
The HLR stores information on subscriber registration and location.
The VLR stores the information loaded from the HLR, including the subscriber registration, location, and status.
The MSC processes the flow of location registration and exchanges data with the VLR.
The MS stores information on its location area.
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Location Registration
Location registration takes place in the following cases:
A MS is switched on.
BSS
Location_ updating_ request
Location_ updating _ accept
MSC / VLR HLR
REGNOT
regnot
IMSI, ESN,calling & called address (SPC)
Registration type, AUTHR, IMSI, ESN, MSCid
auth para required
IMS, MDN,calling feature Indicator, trigger
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Deregistration Deregistration can be initiated by the MS or by the VLR:
Upon receipt of a MS power-off or inactivity indication, the MSC determines the MS needs deregistration.
The MSC/VLR removes all records of the MS from the VLR and sends an MSINACT message to the HLR.
The HLR returns an msinact message to confirm the deregistration.
MSC/VLR
MSINACT
msinact
HLR
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Location Registration (NORMAL)
Location registration takes place in the following cases:
A MS moves beyond the paging coverage area of the previous location area.
LA1 LA2
MS
MSC
Locati on_Updati ng_Request
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Location Registration
Location registration takes place in the following cases:
A MS moves beyond the paging coverage area of the
previous location area.
BSS
Location_updating _ request
Location_ updating_ accept
MSC/VLR N HLR MSC/ VLR O
REGCANCREGNOT
regcanc
regnot
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Location Registration
Location registration takes place in the following cases:
Besides, a MS timely initiates a periodic location registration.
BSS
Location _ updating _ request
Location _ updating _accept
MSC / VLR
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Questions
Whether VLR need to send all the location registrations to
HLR ? And why?
What is the meaning of MSCID in the location registration
message, and what is the function ?
Why does the switch off message need to be registered ?
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Answers Question 1: Not all the requests of location registrations are sent to HLR. If the
subscriber’s data has already existed in VLR and the subscriber is activated, the registration is processed by VLR. Otherwise the registration requests are sent to HLR, and processed by HLR.
Question 2: MSCID is the identification of MSC mainly including SID (System Identification) and SWNO (Switch No.). It uniquely identifies one switch entity, and is used to determine whether the MS is roaming.
Question 3: Switch off registration are mainly used to inform HLR that the subscriber has already powered off. If other subscribers call it, system can send the access refuse directly to the calling party according to the subscriber’s status in HLR.
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HandOff flow on A interface in one BSC
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HandOff flow on A interface between BSCs
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Forward HandOff
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Backward HandOff
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HandOff to Third Party
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Questions
What is the difference between Forward HandOff and Bac
kward HandOff?
When does the third parties handoff happen?
What is the main function of FACDIR ?
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Answers Question 1: the Forward Handoff is that MS handoff from the serving MSC
to a new target MSC; and the Backward HandOff is that MS handoff from the serving MSC to the primary controlling MSC.
Question 2: Whether HandOff to Third Party happens depends on the startup standard value of Third Party HandOff and handoff depth together, when the current handoff times, viz. the handoff depth equal to the startup standard value of Third Party Handoff, the MS will handoff to the third party.
Question 3: FACDIR is used to set up inter_office handoff circuits, which is MAP circuit.
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Chapter 1 Brief Introduction of CDMA FlowsChapter 1 Brief Introduction of CDMA Flows
Chapter 2 Procedures for Mobility ManagementChapter 2 Procedures for Mobility Management
Chapter 3 Procedures for Security ManagementChapter 3 Procedures for Security Management
Chapter 4 Procedures for Basic Call Service and Chapter 4 Procedures for Basic Call Service and
Short Message ServiceShort Message Service
Chapter 5 Procedures for Intelligent Network SerChapter 5 Procedures for Intelligent Network Ser
vicesvices
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Basic Security Management Procedure
This chapter describes functions, principles, and message flows of security
management in the CSOFTX3000. :
Security management of the CSOFTX3000 includes the following:
Authentication
Authentication protects the system resources from illegal users.
Through authentication, the system verifies subscriber validity.
Authentication parameters:
A_Key SSD
RAND/RANDU/RANDBS/RANDSSD
RANDC AUTHR/AUTHU/AUTHBS
COUNT AUTHDATA
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Authentication Principle
For the same algorithm and input on both mobile station (MS)
side and network side, the output results must match. The
principle of CDMA authentication is to compare the output
results by using a same algorithm on the two sides. If the
outputs match, the authentication succeeds.
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Mobile Station Access Authentication Procedures
BSS MSC/VLR HLR/AC
Location Updating Request
AUTHREQ
authreq
REGNOT
regnot
Location Updating Accept
Procedure for authentication upon location registration.
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Mobile Station Access Authentication Procedures
Procedure for authentication upon call origination.
BSS MSC/VLR HLR/AC
CM Service Request
AUTHREQ
authreq
Assignment Request
Assignment Complete
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Mobile Station Access Authentication Procedures
Procedure for authentication upon call termination.
BSS MSC/VLR HLR/AC
Paging Request
Paging Response
AUTHREQ
authreqAssignment Request
Assignment Complete
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Chapter 1 Brief Introduction of CDMA FlowsChapter 1 Brief Introduction of CDMA Flows
Chapter 2 Procedures for Mobility ManagementChapter 2 Procedures for Mobility Management
Chapter 3 Procedures for Security Management Chapter 3 Procedures for Security Management
Chapter 4 Procedures for Basic Call Service and Chapter 4 Procedures for Basic Call Service and
Short Message ServiceShort Message Service
Chapter 5 Procedures for Intelligent Network SerChapter 5 Procedures for Intelligent Network Ser
vicesvices
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Basic Call Procedures
This section describes the procedures for the
following four types of calls:
Intra-Office Calls
Inter-Office Calls
Calls from PLMN to PSTN
Calls from PSTN to PLMN
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Intra-Office Call Procedures (TDM-BASED)
BSC - O MSCe MGW HLR BSC - T
1 . CM Service Request
4 . LOCREQ5 . locreq6 . Paging Request
2 . Add Request
7 . Paging esponse
3 . Add Reply
8. Assignment Request
9. Assignment Complete
16 . CONNECT
13 . Assignment Complete14. Modify Request15. Modify Reply
12 . Assignment Request
10 . Add Request11 . Add Reply
17 . Modify Request18 . Modify Reply
Conversation
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Intra-Office Call Procedures (TDM-BASED)
Conversation
19 . Clear Request
20 Subtract Request
21 Subtract Reply22. Clear Command
25. Subtract Request
27. Subtract Reply
23 . Clear Complete
24 . Clear Command
26 . Clear Complete
.
.
BSC - O MSCe MGW HLR BSC - T
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Inter-Office Call Procedures BSC MSCe- O MGW- O HLR MSCe- T MGW- T BSC
CM Service Request
LOCREQ ROUTREQ
routreqlocreq
Add RequestAdd Reply
Assignment RequestAdd Request
Add ReplyAssignment Complete
INVITE100
Paging RequestPaging Response
183PRACK for 183
200 for PRACK
180PRACK for 180
200 for PRACK
CONNECT200 for INVITE
Modify RequestModify Reply
ACK for 200Conversation
Clear Request BYESubtract RequestSubtract Reply
200 for BYEClear CommandClear Complete
Notify ReplyNotify RequestNotify Reply
Add RequestAdd Reply
Add RequestAdd Reply
Assignment RequestAssignment Complete
Notify Request
Modify RequestModify Reply
Modify RequestModify Reply
Subtract RequestSubtract Reply
Subtract RequestSubtract Reply
Clear CommandClear Complete
Subtract RequestSubtract Reply
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Calls from PLMN to PSTN
BSC MSCe MGW PSTN
CM Service RequestAdd Request
Add ReplyAssignment Request
Add RequestAdd Reply
Assignment CompleteIAM
ACM
RELConversation
RLCSubtract Request
Subtract ReplyClear Command
Clear Complete
ANM
Subtract Request
Subtract Reply
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Calls from PSTN to PLMN PSTN GMSC HLR MSCe MGW BSC
IAM LOCREQROUTREQ
routreqlocreqIAM
Paging RequestPaging Response
Add RequestAdd Reply
Clear CommandClear Complete
ACMACM Modify Request
Modify ReplyCONNECT
ANMANM
ConversationClear Request
Subtract RequestSubtract ReplyREL
REL
RLCRLC
Assignment RequestAssignment Complete
Add RequestAdd Reply
Modify RequestModify Reply
Subtract RequestSubtract Reply
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Questions
What is the difference between the local call and inter-office call?
Please describe the flows triggered when the MS registered in
Beijing makes a call in Shenzhen.
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Answers
Question 1: There are two essential differences between Intra-office mobile
calling and Inter-office mobile calling: one is that whether the location reques
t message carry the TLDN or not, local office assigns the TLDN in intra-office
calling flows, the called office assigns the TLDN in inter-office calling flows; t
he other is that whether the signals route outgoing according as the TLDN.
Question 2: Location Register flow, Authentication flow, Calling flow
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Basic Short Message Procedures
The SMS procedures involve processing the following:
Mobile originated short message
Mobile terminated short message
Short message notification
Short message broadcast
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Mobile Originated Short Messages
MS MSC / VLR MC HLR MSC / VLR MS
SMDPP
smdpp
SMSREQSMSREQ
smsreqsmsreq
SMDPP
SMD - REQ
SMD - ACK
smdpp
SMD- REQ
SMD- ACK
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Mobile Terminated Short Messages
MS BSC MSC/ VLR HLR MC SME
system access Location UpdatingRequest
REGNOT
regnotLocation UpdatingAccept
SMDPP
smdppSMSREQ
SMSREQ
smsreqsmsreq
SMDPPSMD- REQ
SMD- ACK
smdpp
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Chapter 1 Brief Introduction of CDMA FlowsChapter 1 Brief Introduction of CDMA Flows
Chapter 2 Procedures for Mobility ManagementChapter 2 Procedures for Mobility Management
Chapter 3 Procedures for Security Management Chapter 3 Procedures for Security Management
Chapter 4 Procedures for Basic Call Service and Chapter 4 Procedures for Basic Call Service and
Short Message ServiceShort Message Service
Chapter 5 Procedures for Intelligent Network SerChapter 5 Procedures for Intelligent Network Ser
vicesvices
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PPC Service Procedures in Target Network
The PPC service enables a subscriber to open an account and activate voice services by paying beforehand or buying a rechargeable card of a certain value.
Before a call is connected, the system accepts or rejects the call request according to the subscriber's account balance.
During the call, the system decreases the subscriber's account balance for the charge real-time for voice services or other services .
When the account balance reaches a threshold, the system disconnects the call and plays an announcement.
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Calls Originated from PPC Subscribers MGWMSCe SCP
CM Service RequestORREQ
orreqANLYZD
SEIZERESseizeres
CONNRES
Add Request
Add ReplyAssignment RequestAssignment Complete
INSTREQ
SRFDIRModify RequestModify Reply
srfdirinstreqanlyzd
OANSWER
conversation
ODISCONNECT
odisconnect
MS disconnect
Modify RequestModify Reply
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Calls Terminated by PPC Subscribers MSCe HLR SCP
Call originationLOCREQ
locreq
ANLYZD
anlyzd
LOCREQ
locreq
ANLYZD
anlyzd
TANSWER
conversation
TDISCONNECT
tdisconnect
MS answer
MSdisconnect
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Understand the basic flows of CDMA
Understand the meaning of important
parameters
Memorize the abbreviation of messages
SummarySummary
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